1. Field of the Invention
The invention relates to a tubular socket, comprising thermoplastic material, for connecting a fluid conduit to a container, comprising thermoplastic material, wherein the socket has a first part and a second part connected to one another by a two-component injection molding process and wherein the first part has a smaller creep tendency under pressure load and a smaller swellability relative to hydrocarbon-containing fluids than the second part, and wherein the second part and the container are connected by a fusion weld.
2. Description of the Related Art
In a known socket of this kind (DE 42 39 909 C1), the second part is to remain without reinforcement. In practice, it was found however that at higher temperatures, as they occur, for example, in common rail diesel engines within the excess diesel fuel that is returned into the tank by the engine via the socket on the tank, the second part can be thermally deformed when the fluid conduit connected to the socket is simultaneously exposed to greater forces, as they can occur during operation of a motor vehicle. Moreover, the second part that is comprised primarily of high-density polyethylene (HDPE) upon contact with a hydrocarbon-containing fluid, such as gasoline or diesel fuel, can swell more than the material of the first part that is primarily comprised of reinforced polyamide. This can cause cracks within the socket in the vicinity of the connecting location of the two parts. Moreover, HDPE of the second part does not have a sufficiently high diffusion barrier capability relative to hydrocarbon-containing fluids such as gasoline or diesel fuel. On the other hand, it is able to form a fusion-weld connection with the HDPE-containing material of the tank.